Dangerous Level of Air Pollution In Delhi/NCR Air quality is assessed under different Air Quality Index (AQI) categories namely, Good, Moderate, Satisfactory, Poor, Very Poor, and Severe. As per data on AQI in Delhi in NCR, there has been an improvement in the overall air quality in year 2017 as compared to the year 2016. The number of Severe, Poor and Very Poor AQI days were less compared to last year (214 vs. 181). Similarly, the number of Good, Satisfactory and Moderate days were greater than last year (151 against 109). Also, the number of days for Severe Category were less in 2017 as compared to that in 2016 (8 against 28). The Government has taken several steps to address air pollution which inter alia, include notification of National Ambient Air Quality Standards; setting up of monitoring network for assessment of ambient air quality; introduction of cleaner / alternate fuels like gaseous fuel (CNG, LPG etc.), ethanol blending; launching of National Air Quality Index; universalization of BS-IV from 2017; leap-frogging from BS-IV to BS-VI fuel standards from 1st April, 2018; notification of Construction and Demolition Waste Management Rules; banning of burning of biomass; promotion of public transport network; streamlining the issuance of Pollution Under Control Certificate; issuance of directions under Section 18(1)(b) of Air (Prevention and Control of Pollution) Act, 1981 and under Section 5 of Environment (Protection) Act, 1986; installation of on-line continuous (24x7) monitoring devices by major industries; collection of Environmental Protection Charge on more than 2000 CC diesel vehicles; notification of Graded Response Action Plan for Delhi and NCR etc. CPCB has also deployed 40 field inspection teams for pollution hot spots in Delhi NCR and is also co-ordinating with various agencies for reducing air pollution. Episodic high pollution event (Severe+) in Delhi NCR commenced on Nov 07, 2017 and ended on Nov 13, 2017. The continuity of episode days in 2017 was almost same as compared to 2016, however, the meteorological conditions were more critical in 2017 in comparison to 2016 Analysis of pollution episodes in Delhi by CPCB suggests that transitional phase towards winter is always critical due to prevailing meteorological conditions of lower mixing height, higher humidity, fall of ambient air temperature coupled with lower temperature difference between maximum and minimum, calm to low wind speed, etc. Ministry of Earth Sciences vide its report on Scientific Assessment of Delhi Winter Air Quality Crisis " has analysed reasons for episodic high air pollution that commenced on November 07, 2017. As per the System of Air Quality Forecasting and Research (SAFAR) forecasting model, the pollution contribution of Gulf dust storm on peak pollution day of November 08, 2017 was 40% and from stubble burning was around 25%, thereby indicating key role of external factors in the episodic rise". This information was given by Minister of State for Environment, Forest and Climate Change, Dr. Mahesh Sharma in a written reply to a question in Rajya Sabha today.